1. Field of the Invention
The present invention relates to an outdoor cook stove utilizing high pressure gaseous fuel, in particular a stove for domestic or industrial gas cooking using bottled gas, and is suitable for round bottom cooking vessels.
2. Brief Description of the Prior Art
There are various attempts for outdoor stove manufacturers to accommodate cooking for round bottom vessels such as a wok. Barbecue equipment makers make wok adapter to sit on top of fire grid. However the fire grid is not powerful enough and the entire structure is not efficient enough for wok cooking. Authentic, restaurant quality oriental wok cooking requires a stove capable of generating more than 100,000 BTU in power. Such power is beyond reach of single ring low pressure gas stoves. In commercial and industrial wok cooker, as partially illustrated in U.S. Pat. No. 5,315,983, either multi-rings or multiple jet burners are used to achieve the necessary power. Another drawback of using low pressure gaseous fuel is its stove being more susceptible to wind during outdoor cooking.
U.S. Pat. Nos. 5,158,067 and 4,062,341 taught outdoor stove construction for wok cooking. However they share several disadvantages that prevent them from reaching high quality oriental cooking. The first is the low pressure gaseous fuel which prevents their stoves from reaching 100,000 BTU in power. The second disadvantage is the low pressure burner which they utilize does not have center flame heating to the bottom of a wok. As with a bowl shape, it is most important to direct the burning flame toward the bottom of a wok for efficient heat transfer. The disadvantage of not using a center flame is in many burner designs, for example U.S. Pat. Nos. 6,234,064, 6,098,611, D386,936, 4,553,524, 4,353,347. The flame coming out from all these burners spread outward, leaving a sizable center portion of the cooking vessel relying on metal conducting heat back to its center. For a wok, this heat conducting downward to its bottom is extremely inefficient.
Yet another disadvantage of the aforementioned stove constructions is to allow the flame to extend above the wok along its outside surface. Since wok cooking requires an operator to stay closely and maneuver the wok in different ways, the flame coming out can easily burn and hurt the operator. Such examples can be found in U.S. Pat. Nos. 4,062,341, 6,098,611 and 5,775,316. Because of this reason, the operator is forced to reduce power of the stove to stay safe. For low pressure gaseous stove ranges like in U.S. Pat. Nos. 5,044,352 and 5,226,406, expensive exhaust duct mechanism is built for routing the flame and exhaust away from the operator.
U.S. Pat. Nos. 6,234,064, 6,098,611, D386,936, 4,555,616 and 4,353,347 taught to have fixed center burner position with respect to bowl shape cooking vessel. Such fixed position defines fixed heating power distribution to the vessel, forcing the operator to frequently toss foods to various locations in order to receive different heating power. Fixed position between stove and wok greatly restricts the freedom for the operator to tilt and rotate the wok for various food items to receive different flame power, which is necessary when the food items are too fragile to be tossed.
U.S. Pat. No. 4,583,941 taught a burner construction on how to form flame inwardly around an imaginary cylinder. Although the flame is inwardly directed, it still does not heat the center portion of its cooking vessel. Another drawback is that as required by its inward flame, the burner has a bigger chamber for pre-mixed gaseous fuel and air. This big chamber inevitably reduces the mixture gas pressure and hence the power of the burner.
It is the objectives of the present invention to overcome aforementioned drawbacks.
The first objective of the present invention is to utilize high pressure gaseous fuel to achieve highest power for wok cooking with simple burner construction to save cost significantly over traditional high power wok cookers with low pressure gaseous fuel.
The second objective of the present invention is to construct a burner to produce a concentrating inward flame. This flame is directed to the bottom of the cooking vessel (wok) and naturally extends upward along the wok outside surface. In this way heat is first concentrated at the wok bottom and then spread along the outer surface.
The third objective of the present invention is to construct an outdoor stove with a wind guard ring tightly hosting a wok. A portion of the wind guard has openings close to the wok for directing out the flame and exhaust. It also provides access for burner ignition. This portion is to be positioned away from the operator during operation. The rest portion of the wind guard does not have opening to prevent any flame from extending along its side. The operator is positioned along this side for safe operation. This wind guard defines the heating area to the wok and is sized around 8xe2x80x3-10xe2x80x3 in diameter for commonly available woks.
The fourth objective of the present invention is to add a second ring outside the first wind guard to prevent the operator from accidentally touching the hot surface of the first wind guard.
The fifth objective of the present invention is to construct a stove to give complete freedom to the wok operator. The wok is not required to be fixed in position to the stove. The operator can tilt and move the wok in his/her own will at any time in order to achieve best cooking result.
The sixth objective of the present invention is to construct a burner to maintain high gas pressure within the gas chamber before ejecting for ignition. Maintaining high gas pressure all way through the burner guarantees its rated power delivery.
The seventh objective of the present invention is to have burner position adjustable within the stove to accommodate both round and flat bottom cooking vessels for optimum heat transfer.